A stage of stationary vanes in a turbine of a gas turbine engine includes an annular array of stationary vanes. During operation in the turbine, the vanes redirect a flow of combustion gases for delivery at the proper angle to a downstream row of rotating blades. A stage of stationary airfoils in a compressor includes an annular array of stationary airfoils. During operation in the compressor, the airfoils redirect a flow of compressed air. For sake of simplicity, turbine stationary vanes and compressor stationary airfoils are referred to herein as stationary vanes, or simply vanes. A singlet vane includes an inner shroud, an outer shroud, and one airfoil connecting the two, while a vane is generally considered to include an inner shroud, an outer shroud, and one airfoil connecting to an adjacent or multiple adjacent airfoils. Singlets and stationary vanes are referred to herein as vanes. Singlets/vanes may be manufactured by any means. Two or more singlets or vanes may be joined to form a stationary vane sub-assembly.
The stationary vanes are located upstream and downstream of rotating components. The stationary vanes deal with a multitude of stimulation from their rotating neighbors and variations from suction and pressure surfaces of the airfoil as the flow passes over them. The outer shroud of a stationary vane assembly has a hook feature that slides into a casing groove feature. The outer shroud secures the stationary vanes to the frame casing of the gas turbine. The frame casing is a relatively more rigid body than the vane assembly. The casing can carry singular or multiple stationary vane assemblies. In addition, the outer shroud secures the stationary vanes to the frame of the gas turbine engine, and is relatively more rigid than the airfoil of the vane. At the interface between the airfoil and the outer shroud, where the airfoil meets the relatively more rigid outer shroud, known issues of friction, vibration and wear are common.
The main locations of the wear is between the vane's hook to casing grooves and the mating faces of adjacent vanes. As a result, stationary vanes consistently show wear at their mechanical interfaces even though the parts are viewed as stationary components. Consequently, there remains room in the art for improvement